JPS60193153A - Highly corrosion-resistant aluminum alloy for parts in contact with magnetic tape - Google Patents

Abstract

PURPOSE:To improve wear resistance, dynamic friction coefft., machineability and corrosion resistance without spoiling mechanical strength by forming titled parts of aluminum Al contg. a specific weight ratio of silicon Si, copper Cu, magnesium Mg and iron Fe and the balance contg. ordinary impurities. CONSTITUTION:Titled contact parts are constituted of Al contg., by weight, 12% or over and <=22% Si, 1-5% Cu, 0.2-0.8% Mg and 0.1-1.0% Fe and the balance contg. ordinary impurities. Cu increases the strength of the alloy base metal and improves machineability and Si and Mg form Mg2Si deposit and increases the strength of the alloy. Si crystallizes in primary crystal and improves remarkably wear resistance and machineability if the content thereof exceeds 12% but the Si contained at 22% or over makes the plastic working difficult. If Mg exceeds 0.8%, the corrosion resistance is considerably deteriorated and therefore Si is incorporated in a 12-22% range and Mg in a 0.2-0.8 range. Fe is effective in improving the wear resistance and machineability but if the content thereof exceeds. 1.0%, forgeability decreases and therefore Fe is incorporated in a 0.1-1.0% range.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides magnetic tape contact parts such as VTR.
An aluminum alloy with excellent corrosion resistance suitable for parts of magnetic recording devices that come into direct contact with the magnetic tape, such as fixed or rotating tape guiding drums, head drums, etc. It is something that is done.

A VTR is comprised of a rotating magnetic head for magnetically recording and reproducing image signals on a magnetic tape, and a stationary or rotating seven-wheel guide drum for stably running a magnetic hoop. These rotating magnetic heads or parts that come into direct contact with the magnetic tape, such as the tape guide drum, have extremely important functions in maintaining stable tape running without damaging the tape surface, which is covered with magnetic particles. In order to improve the accuracy of reproduced images (image clarity, color unevenness, etc.), there is a strong demand for improvements in materials for magnetic tape contact parts.

Conventionally, tape contact parts for VTRs have been made of, for example, copper alloy with Or hard plating on the surface, or austenitic S.
US materials were used. However, recently, aluminum alloy castings or ingots have been subjected to cutting or plastic processing (particularly forging I) by taking advantage of the advantages of aluminum alloys, such as their light weight, excellent workability, and non-magnetic properties. /
As a result, magnetic tape contact parts such as VTR drums began to be manufactured.

The properties of aluminum alloys used as materials for magnetic tape contact parts include the following.

1) Good abrasion resistance against tape.

2) Low dynamic W and coefficient of friction with the tape, and good tape running properties.

3) Excellent mechanical bullet holes.

4) Excellent machinability and smooth cutting surface.

5) Excellent plastic workability, especially forgeability.

6) Good corrosion resistance in a high humidity atmosphere.

For example, for casting alloy JIS 8 type AI-Al-8i-
Cu-based alloys are excellent in properties 1) to 5) above, but in 6) corrosion resistance in a high temperature and humid atmosphere,
There are the following problems.

If a magnetic tape is wrapped around a VTR cylinder and left in a hot and humid atmosphere for a long time, the cylinder will corrode due to moisture condensing between the magnetic tape and the cylinder, causing rust and damage to the cylinder. Not only does the surface lose its smoothness, which is necessary for the surface, but the rust may also become embedded in the magnetic coating of the magnetic tape, causing the magnetic coating to peel off when the tape is shaved.

As a countermeasure to this problem, Japanese Patent Application Laid-open No. 19472/1983 discloses that a chemically treated film is applied to the surface of a metal or alloy, and the film is applied to a chromium or stainless steel subaru. covered with a tar membrane
! Jru technology has been released. However, this method has the disadvantage that the cost is high because the steps of surface treatment and sputter film coating are added to the normal steps.

In view of the current situation, the inventors of the present invention have conducted various researches to develop an aluminum alloy with excellent wear resistance and corrosion resistance in a high temperature and humid atmosphere for use in magnetic tape contact parts. As a result, high C-no-element Al-
The inventors have completed the present invention by discovering that the tv1g content has a significant effect on corrosion in 8i-Qu-Mil alloys. That is, the object of the present invention is to improve wear resistance, plastic deformation, and wear resistance within the possible range of plastic deformation without impairing mechanical bullet holes.
Motion I? Significantly improved friction coefficient and machinability (chip disposability),
The object of the present invention is to provide an aluminum alloy for magnetic tape contact parts that also has improved corrosion resistance, and this technical problem is solved by the following configuration.

That is, the gist of the first invention of the present application is that 3i exceeds 12% and is 22% or less by weight, and Cu 1.
5%, M (10,2-0.8%, Feo, 1-1.0%
The purpose of the second invention is to provide an aluminum alloy for magnetic tape contact parts with excellent resistance, which is composed of A and L containing ordinary impurities.
More than 2%, less than 22%, C111-5%, Ni0.
5-2.5%, MgO, 2-0.8%, to Fc0yl.
The purpose of the third invention is to provide an aluminum alloy for magnetic tape contact parts having excellent corrosion resistance, which is made of Δ beans containing 1.0% and the rest containing normal impurities. , 22% or less, Cu1-5%, M (10,2-0.8%
, containing 1-1.0% of FeO, roughly 1yln0.2-
1.2%, Oro, 2~1.2% Ura 1 ((Aluminum alloy 1 for magnetic tape contact parts with excellent corrosion resistance, consisting of AI containing one or more elements, and the rest containing ordinary impurities. The gist of the fourth invention is that 1i1rsi exceeds 12%, 22%I-/, lower, C111~5%, Nio,
5"-2', 5%, M (10,2-0,8%, rco,
Contains 1-1.0%, roughly MnO, 2-1.2%, 0.2-1.2% Cr, and one or more elements, and the remainder is normal impurities. Our goal is to provide superior aluminum alloys for magnetic tape contact parts.

The reason for limiting the composition range of the alloy of the present invention will be explained below. In the description of this specification, the content m of the contained elements is all expressed in weight %.

First, the first invention will be explained.

Cu: Cu increases the strength of the alloy base metal and improves machinability. If it is less than 1%, the effect is insufficient, and 5%
If it exceeds this value, castability, forgeability, and corrosion resistance will deteriorate. Therefore, Cu is defined as being in a range of 1 to 5%.

3i and Mg: Si and Mg form vg 2 Si-based precipitates to increase the strength of the alloy. In addition, M improves the mechanical strength of the alloy, especially the yield strength, and further ensures machinability due to its synergistic effect with Cu. Mg is 0.
Below 2%, these effects are not sufficient.

When 3i exceeds 12%, primary silicon crystallizes and the abrasion resistance and bamboo swarf treatment properties are significantly improved.

If Si exceeds 22%, plastic workability becomes difficult at 3°M.
When g is in the Si region of the present application, it significantly affects corrosion resistance in a high temperature and humid atmosphere. That is, when M(1 exceeds 0.8%), the corrosion resistance deteriorates significantly.

This (D, W / Ha 12~22%, -1, M (I
f, 10.2-, in the range of 0.8%.

Fe: Fe has 1q wear resistance and cutting 11 direction -I-
has an f1 effect. When the content is less than 0.1%, no effect is observed, and when it exceeds 1.0%, forging workability decreases.

Therefore, Fe is in the range of 0.1 to 1.0%.

The second invention of this application is to add 0.00% of Ni to the alloy of the first invention.
The wear resistance and machinability are further improved by adding 5 to 25% of 7j. If it is less than 0.5%, no effect will be observed, and if it exceeds 2.5%, coarse intermetallic workpieces will occur.
Forging workability and cutting 1 (1 is 11 (lower. Therefore, Ni
The range is 0.5 to 25%, which is 7%.

The third and fourth inventions of this application add roughly 0.2 to 12% of 1yln, cro, 2 to the alloys of the first and second inventions, respectively.
The wear resistance is roughly improved by adding one or more elements in an amount of 1.2% to 1.2%. If it is less than 0.2%, crystallization that contributes to wear resistance will not be sufficient, and if it exceeds 1.2%, the crystallized substances will become coarse and will impair rigidity. Therefore, 1yln and Cr are in the range of 0.2 to 1.2%.

When manufacturing Arp contact parts made of the alloy of the present invention, the starting material is not a sand mold or metal mold casting, but rather a long ingot produced by a direct cooling continuous casting method with a high cooling rate, and then plastically molded by forging. Most preferably, it is processed and then shaped and finished by mechanical cutting means. In this case, the method for manufacturing aluminum alloys for @-casting described in JP-A-56-19348 is applied to maintain the cooling rate (cooling rate of the solid-liquid interface during continuous casting) at 25°C/second or higher (especially Diameter 1
Small diameter pyrene 1- of 00# or less is suitable for this condition)
If this is done, the mN properties will be greatly improved and long ingots can be extruded]
[Direct forging process without forging] In addition to improving productivity by making the alloy ingot more durable, the structure of the alloy ingot becomes significantly finer, and the second set of grains and particles made of intermetallic compounds are finely and uniformly dispersed. There is. For this reason, it has high bullet holes and is highly wear resistant, and in addition, the surface roughness after so-called mirror finishing is extremely excellent due to the dense and smooth surface required for arc contact parts. □Generally, it has been found that when a precision finished surface is required, such as mirror finishing of metal using a cutting tool using a diamond cutting blade, it is necessary to adjust the structure of the alloy ingot (13 The long ingot (1 diameter) of the alloy of the present invention as described above satisfies such requirements.

However, the alloy material of the present invention is not limited to the 4f continuous υC cast ingot as described above, but also metal molds, sand molds, die cast I
・Form an ingot using Kasa's &4 method, and then use it as it is or after adding heat and cold forging], cut and form it to form a V.
The characteristic effects of the present invention (1) are fully exhibited when the TR-arp contact parts are made of 'MJTi' compared to conventional alloy materials.

The present invention will be explained below based on Examples, but is not limited to the following Examples within the scope of the gist.

Examples and Comparative Examples Table 1 lists Example Alloys 1 to 13 and Comparative Example Alloys.
, 14 to 16 alloy compositions are shown. In the classification of alloy ingots shown in this table, alloy ingot A is produced by the vertical semi-continuous casting method. The cooling speed was maintained at 28°C/sec, and the ingot was manufactured into a long cylindrical ingot with a diameter of 73 mm. It was observed that the two-phase particles were finely and uniformly dispersed.

Alloy ingot B has a diameter of 20 mm obtained by vertical semi-continuous casting method.
A cylindrical ingot of #0 was extruded into a round bar with a diameter of 70 mm.

The alloy ingot C was molded into the shape shown in FIG. 1 by die casting.

The mechanical property test pieces were ingots for alloy materials A and B, and
For alloy material C, 11-grade ingots were heat-treated 1-6, respectively.
! (500℃ x 4 hours, water cooling quenching, then 180℃
After 8 hours of artificial aging treatment), it was processed into a JIS 4D test piece.

Test pieces for evaluating forgeability were prepared by annealing the ingots of both alloy materials A and B (370°C x 4 hours, furnace cooling) and then applying the 4-wedge test 11III shown in Figure 2 (a). (L=1!
i0#, tg-3s, t + = 15m, W = 20m
).

Tests for hardness, machinability, surface roughness, and corrosion resistance were conducted using forging for alloy material Δ and B, and forging gold for alloy material C into the shapes shown in Figure 1. After rough-machining the alloy material, it was subjected to 1-0 heat treatment under the same conditions as above, and then mirror-finished using a right-handed cutting tool on the Gui-7 mondo cutting blade], as shown in Figure 1. Number ＼ J method specifications are D・” 03mm5 d l =40s, d 2
=20m, Ll + = 1h+m, 1-12 =
A VTR rotating drum made of 7mm, J. Lazo is 1! ! The cutting line fl- on the outer circumferential surface of the moving drum has a cutting speed of 150 m/l1li++ and a depth of cut of 0.05 m.
m, cutting] and sending off m was 0.05 mm/rotation.

A specific wear amount test piece was cut out from a part of the above-mentioned V T' 11 rotating drum.

Table 2 shows the characteristics of these specimens.

(Margin below) The outline of each test method is as follows.

b) Tensile strength and elongation A) UJIS4 using 50 ton universal test 1111
A test was conducted using a No. 1 test piece.

C) Forgeability Wedge test piece 1 not shown in Fig. 2 (a) was placed on the anvil 2 shown in Fig. 2 (b) and forged with a 172 ton hammer 3. Evaluation was made by comparing the location of crack occurrence. The evaluation results are: ◎: Good, O: Fair, Δ:
Displayed as slightly defective.

2) Hardness The height directly below the sliding surface of the tape was measured using a Vickers hardness tester.

e) Cutting speed of 150 m using a chip-disposable artificial sintered diamond cutting tool.
/R1111, cutting depth was 0,15, and the shapes of the cutting chips were compared and evaluated. Evaluation result ◎: Good, Q:
Normally, Δ: Slightly inferior is indicated.

f) Surface roughness The surface roughness of the drum in the axial direction was measured using a touch-side roughness tester.

!・) Abrasion resistance Okoshi type abrasion test M (Tested according to IF, with the other party as FC30, friction speed 31rL/sec, load 2.1Kg, friction distance eoom, no + ISI, and the ratio per unit area The amount of wear was measured.

B) A corrosion-resistant VTR drum was strung together with a magnetic tube to which 60 g of T was applied and held in an atmosphere of 40°C and 85% humidity for 131 hours, and then the drum and magnetic decoupler were placed. The condition of the /C portions of each contact area was observed.

The evaluation was in four stages. That is, ◎No change in NiDrum or magnetic tape.

Small corrosion occurred on the Oni drum, but there was no abnormality on the magnetic tape.

Corrosion occurred on the Δni drum, and magnetic powder flaked off in some places on the magnetic °arp.

×Nidram is noticeably corroded, and the magnetic powder on the magnetic tape is noticeably exposed.

At the above Hr value, O and O are of a level that does not pose a problem for practical use.

FIG. 3 shows a sketch of the surface of the drum that was rated 111 by the corrosion resistance test, and FIG. 4 shows a corresponding sketch of the magnetic tape. In both Figures 3 and 4, (a) is alloy N.
o, 2, (b) Gma alloy I! I, 14GL: Compatible Su? :l. In Figure 3 (b), the black dots on the drum surface are corroded areas, and in Figure 4 (b), the black dots on the tape surface are due to drum corrosion. be.

When we observed the structure of the cross section of the seaweed area in Figure 3 (11), we found that
It is clear that corrosion is intergranular corrosion that propagates to grain boundaries. A microscopic photograph of the new surface of the corroded part of the drum in FIG. 3(b) is shown in FIG.
Corrosion resistance when the drum and magnetic tape are statically sold under high temperature and high humidity while in contact with each other can be achieved by controlling the Si and Mg contents.

As seen in the characteristic values in Table 2, the alloy of the present invention has excellent mechanical 1/1 quality required for magnetic tape contact parts,
In addition, it has excellent corrosion resistance even without special treatment such as coated ink on the surface of the part, making it extremely suitable as a material for J3 and 1 air contact parts.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a rotating drum shape test for VTR, Figure 2 (a) is the shape of a wedge test piece for forgeability evaluation, and Figure 2 (b) is a forgeability test method. 3 and 4, the drum surface (Fig. 3) and the corresponding magnetic tape (Fig. ), in which (a) corresponds to metal-containing tooth 2 and (b) (metal-containing tooth 14), respectively.
11 microscope sets 11'A'ri true. Patent Applicant 1 (Wa Light Metal Co., Ltd. Agent Patent Attorney Sei Kikuchi - Fan 1 Tutun 2 Oni 3 Fig. 4 (α) (b) Child 5

Claims (1)

[Claims] 1. 3i by weight exceeds 12% and is not more than 22%, Cu1~
5% MQo, 2-0.8%, Feo, 1-1.0%, and the balance is made of An containing ordinary impurities, and has excellent corrosion resistance for use in magnetic tape contact parts. 2. 3 i by weight is more than 12% and less than 22%, Cu1
~5%, NiO, 5-2.5%, Mg0.2-0.8%
, FeO, 1 to 1.0%, and the remainder is A I containing ordinary impurities, and has excellent corrosion resistance for use in magnetic tape contact parts. 3. 3i by weight exceeds 12% and is 22% or less, Cu1~
5%, M (10,2-0.8%, FeO, 1-1,0%
Contains roughly MnO, 2-1.2%, Cr0.2=1
．． An aluminum alloy for use in magnetic tape contact parts having excellent corrosion resistance and comprising at least one element out of 2% and the remainder containing ordinary impurities. 4. Si is more than 12% and less than 22% by weight, Cu1~
5%, NiO, 5-2.5%, Mgo, 2-0.8
%, FeO, 1-1.0%, Zara 1yjn0.2-1.2%, Cr0.2-1.2
An aluminum alloy for magnetic tape contact parts having excellent corrosion resistance and consisting of ΔA, which contains one or more elements in % and the remainder contains ordinary impurities.